Sorry, didn’t see the notification on this. You definitely need to use the CubeOrange firmware build. It will bomb out if you try to load CubeBlack, CubeGreen, CubeSolo, etc. The USB dev IDs and hardware drivers are different so you need to use the CubeOrange build.
But you can then load the parameter file used by the green cube onto it. The parameters that matter to the Solo are the same and compatible across the boards. I put the BRD_PWM_VOLT_SEL parameter in both the files so it will always be on when you load it onto an orange.